Many are aware that some medications don’t work well together. But what you eat and drink can also affect the way your medications work. A food-drug interaction can cause a side effect from a medication to get worse, better, or even cause new side effects. Before you take a medication for the first time, it is important to talk with your doctor or pharmacist to check for anything you should stay away from.
Grapefruit changes the way certain cells in your gut take in and move medication through your body. In fact, it can affect more than 50 drugs—making some less effective and others too strong. For example, some drugs, like statins used to lower cholesterol, are broken down by enzymes. Grapefruit juice can block the action of these enzymes, increasing the amount of drug in the body and may cause more side effects. Other drugs, like fexofenadine used to treat allergies, are moved by transporters into the body’s cells. Grapefruit juice can block the action of transporters, decreasing the amount of drug in the body, and may cause the drug to not work as well.
Dairy products such as milk, yogurt, and cheese can interfere with certain medications, including antibiotics, such as tetracycline, doxycycline, and ciprofloxacin. These antibiotics may bind to the calcium in milk, forming an insoluble substance in the stomach and upper small intestine that the body is unable to absorb. If you’re taking antibiotics, make sure to find out about the foods or beverages you should stay away from.
This would appear to be a fairly harmless snack food. However, for someone taking digoxin, used to treat congestive heart failure and abnormal heart rhythms, some forms of licorice may increase the risk for medication toxicity. Licorice may also reduce the effects of: blood pressure drugs; diuretic (urine-producing) drugs including hydrochlorothiazide and spironolactone; and cyclosporine, used to keep people who’ve had transplants from rejecting their new organs.
Dark chocolate, in particular, can weaken the effects of drugs meant to calm you down or make you sleep, like zolpidem tartrate. It also can boost the power of some stimulant drugs, like methylphenidate. If you take a MAO inhibitor, used to treat depression, it can make your blood pressure dangerously high.
If you take a drug used to treat and prevent blood clots, be aware of how much vitamin K you take in. It can make the medication less effective and put you at higher risk of a dangerous blood clot. Broccoli, Brussels sprouts, kale, parsley, and spinach are some of the most common foods high in vitamin K.
If you are taking any sort of medication, it’s recommended that you avoid alcohol, which can increase or decrease the effect of many drugs. Some interactions are more serious than others. For instance, when combined with alcohol, analgesics/antipyretics and nonsteroidal anti-inflammatory drugs (NSAIDs), used to relieve mild to moderate pain and lower fever, can cause liver damage and stomach bleeding. You should talk to your doctor about any alcohol you use or plan to use.
Coffee can keep some common medications from working properly. With some drugs, the interaction is caused by caffeine; with others, its coffee’s other compounds that have an effect. Coffee has shown to weaken antipsychotic drugs like lithium and clozapine, but boost the effects— and side effects—of other drugs. Those include aspirin, epinephrine (used to treat serious allergic reactions), and albuterol (taken by inhaler for breathing problems). It can also make it harder for your body to take in and use iron.
Ginseng can make you more likely to have internal bleeding if you take the blood thinners heparin or aspirin, as well as NSAIDs, like ibuprofen or naproxen. If you take MAO inhibitors, ginseng can cause headaches, sleep problems, hyperactivity, and nervousness. This herb can interfere with the bleeding effects of Coumadin.